Gliederung

Objective: In spine surgery, large progress has been made in stabilizing procedures with the use of transpedicular and transarticular screw placements. Since the mid 90`s spinal navigation tools to place these screws more safely have been evolved. There is still an ongoing debate on the necessity for spinal navigation and on the legal aspects of not using this technology. In this study we examined the usefulness of spinal navigation in relation to different stabilization procedures.

Methods: 258 drill holes were placed in plastic vertebrae (Sawbones,USA) according to a strict randomized protocoll simulating the following spinal standard procedures: transpedicular drilling of the cervical, thoracic and lumbar spine, transarticular drilling at C1-C2, transarticular transfacet drilling of the lumbar spine and lateral mass drilling of the cervical spine. Three insertion techniques were compared: conventional fluoroscopy-guided drilling, drilling with the help of virtual twodimensional fluoroscopy and navigated threedimensional drilling using preoperative CT scans and intraoperative Fluoro – CT – matching. Navigational drillings were performed with the vector vision2 – System, version 5.02 (BrainLab, Munich,Germany). All drill holes were evaluated with CT scans and deviations were measured on the PC screen using commercial software. Comparisons were made using standard statistical software.

Results: Overall results depicted a worse rate of correct drill hole placements with virtual fluoroscopy compared to conventional and threedimensional drillings(p<0,001). Analysis of the subgroups according to the respective procedure revealed better rates of correct drillings with threedimensional navigation for transarticular C1-C2 drilling and transpedicular drilling of the cervical spine. Transarticular transfacet drilling of the lumbar spine was done most safely with an aiming device. No significant differences were found for all other procedures.

Conclusions: Although relatively exact when used properly, spinal navigation tools have only a limited usefulness. Spine surgeons should be aware of procedure – depending impact of spinal navigation. Virtual twodimensional fluoroscopy appears to have too many drawbacks to be recommended generally for clinical use.